Gérard Mourou

Interview

“It’s an amazing moment. Nobody is prepared for that kind of moment”

Telephone interview with Gérard Mourou following the announcement of the 2018 Nobel Prize in Physics, 2 October 2018. The interviewer is Adam Smith, Chief Scientific Officer of Nobel Media.

Interview transcript

Gérard Mourou: Hello.

Adam Smith: Hello, my name is Adam Smith from Nobelprize.org.

GM: Yes.

AS: Yes. Many congratulations on the award of the Nobel Prize.

GM: Thank you very much.

AS: It must be … it must be an amazing environment.

GM: It’s an amazing moment, I tell you. And nobody’s prepared for that kind of moment.

AS: I must say it sounds quite calm around you now.

GM: Yeah.

AS: In the background it sounds calm.

GM: The background, yeah, because I’ve been put in a room, you know, so nobody can bother me.

AS: Going back to that breakthrough in 1985, was there a eureka moment when you suddenly realised how you could improve the pulse length, shorten the pulse length?

GM: It came you know in different steps, in different steps, and in fact it came very, very kind of naturally with what I was doing. So we wanted to amplify very, very short pulses, you know, in order to get more peak power. OK, because, you know power is energy divided by time, and so if you want to get large power, big power, then you try to get pulses shorter and shorter and shorter, OK. So trying to do that, you know, so when you amplify your pulse, come to a point where, you know, material is breaking down on the laser.

AS: Yes, so you have to reduce the power somehow.

GM: You have to reduce the power but not change the energy, right, I mean you have to reduce the power without changing the energy, without changing the total energy of the pulse, OK, because you want to do that efficiently. So, you know I just came say well maybe we can stretch the pulse, stretch the pulse, and we knew how to do that because we were working on, recently on very short pulses, and you knew how to stretch pulses by using diffraction gradings and so on. So we stretched the pulse, and of course immediately the peak power decreased and then we could amplify the pulse much better, much much better. And, and then we had to compress it back. So again, again you know, by steps, you know.

AS: Yes, and what … give me an example of one of the most exciting things we can do with these ultrafast lasers.

GM: Well, what we can do is to accelerate particles. We can accelerate particles with really stunning efficiency, so instead of using kilometres to accelerate particles, right, like at CERN, you know, we could use a system with lasers which will already only take centimetres.

AS: Indeed, indeed.

GM: And, you know accelerators have a lot of applications, you know, in the medical world, OK, because you want to create for example therapy, OK, therapy you [unclear] maybe use maybe radio isotopes, you know, but every time when you want to do that you have, you know, you have sometimes to go outside, so this radio isotope, for instance, are made, you know, by reactors which are far away, and so on, so it’s difficult to bring them back at the patient’s bed.

AS: Yes.

GM: But now if you really make this accelerator very compact you can put that then in hospitals, and because they are compact, you know, you can multiply them, you know, and you can have one per hospital.

AS: Powerfully described. It’s a most lovely example of such a successful interaction between basic science and applied science. The whole development…

GM: Oh absolutely, absolutely, absolutely, yep.

AS: And how utterly co-dependent they are – you cannot do it without the basic research.

GM: Yeah.

AS: Yeah, and it’s so exciting that you’ve been awarded together with your graduate student.

GM: That too, yes, yes, yes. You know, when I proposed this idea to Donna Strickland she said: ‘Well that’s so simple, you know, this is not a PhD’. You know … [Laughs]

AS: Well…

GM: No, it’s not a PhD, it’s Nobel Prize material!

AS: I don’t know of another example where somebody’s first published scientific paper leads eventually to a Nobel Prize. That sets a pretty high standard for other graduate students to achieve.

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This year 12 new laureates have been awarded for achievements that have conferred the greatest benefit to humankind.

Their work and discoveries range from cancer therapy and laser physics to developing proteins that can solve humankind’s chemical problems. The work of the 2018 Nobel Laureates also included combating war crimes, as well as integrating innovation and climate with economic growth. Find out more.

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